2.3.3 GI Motility and Dysmotility III

Question 1

Increases in what will cause the stomach to switch from rapid emptying to slow emptying?

Answer 1

Viscosity

Particle size

Calories and Osmo

Question 2

Nutrients can regulate what neuronal input in gastric emptying?

Answer 2

Work via Vagus nerve and enteric nervous system

Question 3

What are the characteristics of slow emptying?

Answer 3

low fundus tone, narrow pylorus, contracted duodenum and retropulsion is favored

Question 4

What is the Pylorus state?

Answer 4

when pylorus is open and middle antrum contracts, duodenum does not contract and allow emptying

Question 5

What is the role of neurotransmitters on the muscle contractions of the stomach?

Answer 5

Required for smooth muscle contractions

Question 6

What is pyloric stenosis?

Answer 6

Narrowing of the pylorus due to thickening of pylorus

Projectile VOMITING

Question 7

What is dumping syndrome?

Answer 7

rapid emptying due to surgery, vagotomy, peptic ulcers, cyclic vomiting, drugs

Early and late dumping syndrome

Question 8

What is phase 1 of the fastering motor pattern? (between meals)

Answer 8

quiescent, little to no contractions

Question 9

What are the ICC in the stomach?

Answer 9

interstitial cell of Cajal → each other and smooth mm (via gap junctions) and myenteric ganglia (varicosities)

Cells have spontaneous electrical rhythmicity

Question 10

What is the role of the esophagus in gastric filling?

Answer 10

bolus activates inhibitory enteric nerves via vagus n. to relax LES

Question 11

How does gastric emptying change between a glucose solution, protein solution, and solid meal?

Answer 11

Question 12

What is electrogastrography?

Answer 12

detection of slow propagating waves, slow/fast

Question 13

What is breath testing?

Answer 13

labeled octanoate, appearance of CO2 associated with gastric emptying

(slow appearance = poor emptying)

Question 14

What are the characteristics of rapid emptying?

Answer 14

high fundus tone

wide pylorus

relaxed duodenum

propulsion is favored

Question 15

What are some of the mechanisms of delayed gastric emptying?

Answer 15

Abnormal slow waves

Damage to enteric nervous system

Increased resistance: pyloric stenosis and diabetic pylorospasm

Question 16

What is gastroparesis?

Answer 16

delayed emptying, due to ↓ driving force or pyloric obstruction, common w/ diabetes, sclerosis, surgery

Question 17

What is scintigraphy?

Answer 17

gamma radiation consumed to generate image over time

Question 18

What is phase II of the fasting motor pattern?

Answer 18

irregular contractions

Question 19

Duodenal gastric reflux can be caused by?

Answer 19

Pyloric incompetence

Question 20

What is barium radiography?

Answer 20

ingestion of radioactive material and XRay taken

Question 21

What is the basal electrical rhythm associated with ICCs?

Answer 21

ICC cells maintain this rhythm of depolarization due to Ca++ and K+ flux, may not result in mm contraction

Question 22

Describe terminal antral contraction and grinding

Answer 22

Contractions of terminal antrum forces particles back through, which causes them to break down into smaller sizes

Question 23

What is the role of the fundus in gastric filling?

Answer 23

efferent nerves tell gastric mm relax for meal

Question 24

What are the local and vaso-vagal pathways in gastric relaxation?

Answer 24

NO and VIP signal for relaxation

Question 25

What is the role of the duodenum in gastric filling?

Answer 25

nutrients and bolus activate vagus to inhibit motor neurons

Question 26

Describe the different phases of the antral pump

Answer 26

Question 27

What can cause tachygastria?

Answer 27

Abnormal pacemarker which is abnormally fast

Question 28

What is the role of the pacemaker cell in the stomach?

Answer 28

Pacemaker – located in body (corpus) produces slow propagating waves

Question 29

What is the difference between propulsion, gastric emptying, and retropulsion?

Answer 29

Propulsion - proximal antrum contracts filling distal antrum

Gastric emptying - middle antrum contracts emptying

Retropulsion - Distal antrum contracts and granding (movement of chyme in oral direction)

Question 30

What is the function of the proximal portion of the stomach?

Answer 30

accommodation of incoming meal, reservoir, receptive relaxation, tonic contractions

Question 31

What is diabetic gastroparesis?

Answer 31

Generation of slow waves that may originate from ICC (dysrhythmias)

Pathway for slow wave propagation

Loss of ICC can impair neural imputs

Question 32

What are the 3 mechanisms that regulate gastric reservoir function?

Answer 32

Stimulation of pharynx and esophagus activates inhibitory enteric nerves via vagus

Can be triggered by distension leading to activation of vagusor enteric neurons

Nutrients or stretch in duodenum or distal gastric regions activate vagal or enteric pathways leading to inhibition of motor neurons

Question 33

Phase III is important in?

Answer 33

Allows for emptying of the stomach that might have not occured in the normal digestive phase

Question 34

What are the properties of the slow waves of the stomach?

Answer 34

propagate quickly across stomach and slowly down the stomach

Question 35

What is the sieving function of the stomach?

Answer 35

smaller particles on top exit during emptying when middle antrum contracts

Question 36

What is phase III of the fasting motor pattern?

Answer 36

regular contractions, open pylorus

Question 37

What are some causes of increased gastric emptying?

Answer 37

Decreased fundic compliance

Loss of pyloric resistance

Failure of duodenal feedback

Question 38

What is the function of the distal portion of the stomach?

Answer 38

pump, mixing and grinding, phasic contractions